A seed density sorting and grading apparatus and method

Abstract

The application provides a seed density selection and grading device and method, which comprises a liquid quantitative preparation module, a density separation module, a liquid recycling module and a liquid filtration module. The liquid quantitative preparation module is used for configuring a liquid with a preset density and delivering the liquid to the density separation module. The density separation module is provided with a bin body for separating seeds with different densities. The density separation module delivers the separated seeds to the liquid recycling module. The liquid recycling module separates the seeds from the liquid. The separated liquid is delivered to the liquid filtration module. The liquid filtration module filters the liquid for recycling. The application is highly automated, realizes rapid separation of seeds and liquid, rapid drying of seeds, and efficient recycling of liquid, reduces manual intervention, improves work efficiency and accuracy, and reduces labor intensity and cost. The liquid buoyancy characteristics can accurately separate the same batch of seeds into multiple levels according to density, significantly improving the uniformity of seed germination.

Description

Technical Field

[0001] This invention relates to the field of seed selection and grading equipment, and in particular to a seed density selection and grading equipment and method. Background Technology

[0002] Seed selection and grading are crucial for improving seed quality and ensuring healthy crop growth and high yields. In tobacco cultivation, seed quality directly affects the quality and yield of tobacco leaves, making precise and efficient seed selection particularly important. Currently, tobacco seed selection mainly relies on two traditional methods: winnowing and screening.

[0003] However, these methods have obvious shortcomings: poor sorting accuracy, making it difficult to achieve high-precision seed grading; they can easily cause mechanical damage to seeds, affecting their germination ability and later growth performance; especially for aging and deteriorated stored seeds that cannot be improved in quality after repeated winnowing and screening, seeds that have not completed physiological maturity and cannot be stored, and rare and valuable flower and medicinal seed seeds, the effects of traditional methods are very limited.

[0004] Achieving high-precision grading of tobacco seeds has become a major challenge restricting the development of tobacco seed processing technology. This issue not only concerns the further improvement of tobacco seed quality but also involves enhancing precision processing capabilities, thereby promoting the high-quality development of the entire tobacco seed industry. Currently, the industry lacks systematic, suitable, and widely applicable density sorting technologies and supporting equipment.

[0005] Currently, liquid density sorting technology can effectively overcome the limitations of traditional methods. Static density sorting utilizes the buoyancy of liquids, causing seeds immersed in the liquid to naturally stratify according to their density—low-density seeds float on the surface, medium-density seeds suspend in the middle, and high-density seeds sink to the bottom. This method can achieve highly precise grading of seeds within the same batch. However, despite the significant advantages shown by liquid density sorting technology, it remains in the laboratory stage and has not yet been put into actual production. There is currently no systematic, suitable, and widely applicable density sorting technology and supporting sorting equipment. Therefore, this paper proposes a seed density sorting and grading device and method to solve the aforementioned problems. Summary of the Invention

[0006] In view of this, the present invention provides a seed density sorting and grading device and method, which aims to solve the problems in the prior art where existing liquid density sorting technology cannot achieve systematic and mass production.

[0007] This invention provides a seed density selection and grading device, including a liquid quantitative preparation module, a density separation module, a liquid circulation and recovery module, and a liquid filtration module. The liquid quantitative preparation module prepares a liquid of a preset density and delivers it to the density separation module. The density separation module is equipped with a chamber for separating seeds of different densities. The density separation module delivers the separated seeds to the liquid circulation and recovery module, which separates the seeds from the liquid. The separated liquid is then delivered to the liquid filtration module, which filters the liquid, enabling its recycling.

[0008] Based on the above scheme, a liquid storage module is also included. The liquid filtration module stores the filtered liquid in the liquid storage module, and the liquid quantitative preparation module can also store the prepared liquid in the liquid storage module.

[0009] Further description of the aforementioned scheme: the liquid quantitative preparation module includes a mixing module, a metering pump, a hexane storage tank, and a dichloromethane storage tank. The hexane and dichloromethane storage tanks are sealed and stored respectively. Two metering pumps are provided, which quantitatively pump the hexane and dichloromethane into the mixing module respectively. The mixing module includes a mixing motor, a mixing tank, and a paddle. The mixing motor drives the paddle to stir and mix the hexane and dichloromethane in the mixing tank.

[0010] Furthermore, an inlet pump and a storage tank are installed between the liquid quantitative preparation module and the density separation module. The inlet pump draws the liquid from the mixing tank to the storage tank. A valve is installed at the bottom of the storage tank and is connected to the pipeline of the density separation module to quantitatively deliver the prepared liquid to the density separation module.

[0011] Further describing the aforementioned solution, the density separation module includes a lower chamber, a valve, and an upper chamber. The valve is located between the lower and upper chambers to separate seeds of different densities. The lower chamber is connected to the liquid circulation and recovery module via a pipe. Optionally, the valve between the lower and upper chambers is a three-way valve, which can simultaneously discharge the seed solution from both chambers to the liquid circulation and recovery module.

[0012] Furthermore, the lower chamber of the density separation module is a double-conical container, and the upper chamber is a conical container. An electric straight-through valve is installed between the lower and upper chambers. The lower and upper chambers also include nozzles and vibrators. The nozzles are connected to the liquid storage tank and spray the seeds attached to the inner wall of the chamber to make them fall to the bottom of the container. The vibrator vibrates the liquid and seeds to promote the rapid stratification of seeds of different densities.

[0013] Further description of the aforementioned scheme: the liquid circulation and recovery module includes a sealed tank with two collection trays on both sides. Below the collection trays is a conical liquid collection hopper, which is connected to the liquid filtration module. Above the collection trays are two feed pipes, which are connected to the density separation module via three-way valves. The three-way valves distribute seeds of different densities to different collection trays. The collection trays are installed in a drawer-type seal on both sides of the sealed tank and are equipped with filter holes for separating seeds from liquid.

[0014] Optionally, the sealed container is also connected to a drying system. The air inlet of the drying system is located above the collection tray, and the air outlet is located on the side of the sealed container. The drying system dries the seeds on the collection tray.

[0015] Further description of the aforementioned scheme: the liquid filtration module includes a filter, which is provided with at least a first filter cartridge and a second filter cartridge. Filter cotton is provided inside the first filter cartridge and the second filter cartridge. Three-way valves are provided at both ends of the first filter cartridge and the second filter cartridge. The three-way valve at the liquid inlet end of the filter cartridge is connected to the liquid circulation and recovery module, and the three-way valve at the liquid outlet end of the filter cartridge is connected to the liquid inlet pump.

[0016] The present invention also provides a seed density selection and grading method, including the above-mentioned seed density selection and grading equipment, comprising the following steps:

[0017] S1: The liquid quantitative preparation module quantitatively pumps n-hexane and dichloromethane stored in the storage tank into the mixing tank of the mixing module, and the impeller inside the mixing tank stirs and mixes the liquid.

[0018] S2: The mixed liquid is pumped into a storage tank for later use;

[0019] S3: The seed tank puts a quantitative amount of seeds into the density separation module, and the liquid storage tank delivers a quantitative amount of liquid to the density separation module;

[0020] S4: The vibrator vibrates the liquid and seeds in the density separation module, causing seeds of different densities to quickly separate into the lower and upper chambers, and the straight valve closes the channel between the lower and upper chambers.

[0021] S5: The three-way valve at the bottom of the lower compartment switches to the high-density seed collection tray side, discharging the liquid and seeds in the lower compartment into the high-density seed collection tray of the liquid circulation and recovery module, and the nozzle sprays onto the lower compartment wall to blow off the seeds attached to the inner wall of the compartment; the three-way valve switches to the low-density seed collection tray side, and the straight-through valve opens, discharging the liquid and seeds in the upper compartment into the low-density seed collection tray of the liquid circulation and recovery module;

[0022] S6: After the liquid enters the filter, the liquid in the liquid circulation and recovery module passes through the inlet pump, which pumps the filtered liquid to the storage tank.

[0023] S7: The drying device dries the seeds in the collection tray.

[0024] The seed density selection and grading equipment and method provided by this invention have significant advantages and wide applicability:

[0025] High-precision grading: Utilizing the buoyancy properties of liquids, seeds in the same batch can be accurately divided into multiple layers according to density, significantly improving the uniformity of seed germination, which is especially important for crops such as tobacco seeds that require high germination rates.

[0026] Reduced mechanical damage: It avoids the physical damage that may be caused to seeds during traditional wind selection and screening processes, protecting the integrity and germination ability of seeds, and is especially suitable for fragile seeds such as rare and precious flower and medicinal seed seeds.

[0027] Environmentally friendly and economical: It enables efficient recycling of sorted liquids, reduces resource consumption and environmental pollution, and reduces the amount of chemicals used, which is in line with the development trend of green agriculture.

[0028] Wide range of applications: It is not only suitable for tobacco seeds, but can also be extended to other types of small seeds, such as vegetables, grains, and oil crops. It is highly adaptable and has broad application prospects.

[0029] High degree of automation: The entire process is highly automated, reducing human intervention, improving work efficiency and accuracy, and reducing labor intensity and costs.

[0030] Easy and safe to operate: The well-designed operating procedures and safety protection measures ensure the safety of operators and the long-term stable operation of the equipment, making it particularly suitable for large-scale industrial production.

[0031] Data traceability: By combining modern information technology, data from each sorting can be recorded and detailed reports can be generated, facilitating subsequent quality traceability and management, and helping to establish a sound seed quality management system.

[0032] In summary, this invention provides a systematic, suitable, and scalable seed density selection and grading technology and supporting equipment, offering an effective solution to the current bottleneck problems in the tobacco seed processing field and promoting the development of the tobacco seed industry and related fields to a higher level. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram provided for an embodiment of the present invention;

[0035] Figure 2 , 3 This is an overall schematic diagram provided for an embodiment of the present invention;

[0036] Figure 4 This is a partial structural diagram provided for an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of a filter and a liquid circulation and recovery module provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the density separation module structure provided in an embodiment of the present invention;

[0039] Figure 7 A cross-sectional view of the density separation module provided in an embodiment of the present invention;

[0040] Figure 8 This is a cross-sectional view of a liquid recycling module provided in an embodiment of the present invention.

[0041] The following are the labeling elements in the figure:

[0042] 1. Density separation module; 11. Lower chamber; 12. Straight-through valve; 13. Upper chamber; 14. Nozzle; 15. Vibrator; 2. Liquid circulation and recovery module; 21. Collection tray; 22. Three-way valve; 23. Feed pipe; 24. Liquid collection hopper; 25. Drain pipe; 3. Filter; 31. First filter cartridge; 32. Second filter cartridge; 33. Solenoid valve; 34. Recovery pipe; 4. Inlet pump; 5. Storage tank; 6. Seed tank; 7. Mixing module; 71. Mixing motor; 72. Mixing tank; 8. Metering pump; 9. Recovery bucket; 91. Hexane storage tank; 92. Dichloromethane storage tank.

[0043] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] Please see Figures 1 to 8 As shown, this invention provides a seed density selection and grading device, which includes the following main modules: a liquid quantitative preparation module, a density separation module 1, a liquid circulation and recovery module 2, a liquid filtration module, and a liquid storage module. Wherein:

[0047] Liquid metering module: Used to prepare liquids of preset density and deliver them to density separation module 1. This module includes mixing module 7, metering pump 8, hexane storage tank 91, and dichloromethane storage tank 92. Hexane and dichloromethane are separately sealed and stored in their respective storage tanks 5. Two independent metering pumps 8 meterly draw these two solvents into mixing module 7. Mixing module 7 is equipped with mixing motor 71, mixing tank 72, and impeller. Mixing motor 71 drives the impeller to uniformly stir the liquid in mixing tank 72. Hexane and dichloromethane storage tanks 92 are made of stainless steel or high-density polyethylene (HDPE). These materials resist solvent corrosion, ensuring long-term stable use. All seams and connections in storage tank 5 must have good sealing performance to prevent liquid leakage or evaporation. Teflon lining or other forms of high-efficiency sealing devices can be used. Ventilation system: Appropriate vents or breather valves should be installed on the top of storage tank 5 to regulate internal pressure, and a gas detector should be equipped to monitor the gas concentration inside the tank in real time to ensure safety. It should be noted that other inorganic and organic solvent liquid separation media of different densities can be selected; however, only n-hexane and dichloromethane are used in this embodiment. The metering pump 8 is a diaphragm metering pump. The diaphragm metering pump 8 possesses high precision, safety, reliability, and corrosion resistance. The diaphragm design prevents the risk of chemical leakage, protects operator safety, and can resist the corrosive effects of n-hexane and dichloromethane, extending its service life.

[0048] Density separation module 1: This module has a dedicated compartment for separating seeds of different densities. For example... Figure 6 , 7As shown, the module includes a lower chamber 11, a straight-through valve 12, and an upper chamber 13. The lower chamber 11 is a double-conical container, and the upper chamber 13 is a conical container. An electrically operated straight-through valve 12 is installed between the lower chamber 11 and the upper chamber 13 to separate seeds of different densities. The lower chamber 11 and the upper chamber 13 are also equipped with nozzles 14 and vibrators 15. The nozzles 14 are connected to the liquid storage tank 5 and are used to blow off seeds adhering to the inner wall of the chamber. The vibrator 15 promotes rapid stratification of liquid and seeds. The vibrator 15 is typically driven by an electric motor or an electromagnetic drive. When current passes through the coil, it generates reciprocating or rotational motion under the action of a magnetic field, which is then converted into vibration output. To effectively transmit the vibration to the seeds and liquid inside the chamber, the vibrator 15 may be directly mounted on the chamber wall or indirectly connected through an elastic connector. This ensures that the vibration energy is evenly distributed throughout the separation space, avoiding local over-vibration or under-vibration. In some embodiments, an ultrasonic vibrator 15 may also be used. The ultrasonic vibrator 15 converts electrical energy into high-frequency mechanical vibration through a transducer, typically exceeding 20 kHz. This vibration propagates into the liquid at an extremely high frequency, generating minute but efficient disturbances. When the ultrasonic waves propagate in the liquid, they form microbubbles in localized areas, a phenomenon known as cavitation. These bubbles rapidly expand and collapse, generating strong localized shock waves and microjets, which help disrupt the surface tension of the liquid, accelerate the relative movement between seeds, and promote the rapid separation of seeds of different densities. It should be noted that this embodiment only includes an upper chamber 13 and a lower chamber 11. In other embodiments, more chambers can be provided as needed to separate seeds of various densities. It should also be noted that in other embodiments, a three-way valve can be installed between the lower chamber 11 and the upper chamber 13, allowing the seeds and liquid in the upper chamber 13 to flow directly to the liquid circulation and recovery module 2. Simultaneously, the liquid circulation and recovery module 2 can contain two separate collection tanks for collecting seeds of different densities.

[0049] Liquid recycling module 2: such as Figure 5 , 8As shown, the liquid circulation and recovery module 2 is responsible for separating the separated seeds from the liquid, and the collection tank collects seeds of different density levels. This module includes a sealed tank with two drawer-type sealed collection trays 21 on both sides, and a conical liquid collection hopper 24 below. The bottom of the liquid collection hopper 24 is connected to the liquid filtration module via a drain pipe 25. The feed pipe 23 is connected to the density separation module 1 via a three-way valve 22, which distributes the seeds to different collection trays 21 according to their density. The sealed tank is also connected to a drying system. The air inlet of the drying system is located above the collection trays 21, and the air outlet is located on the side of the sealed tank. The drying system dries the seeds on the collection trays 21 (not shown in the figure). It is important to note that a sealing ring is installed between the collection trays 21 and the sealed tank to achieve a sealed installation and prevent leakage of hexane and dichloromethane. In other embodiments, the drying system is set up separately and is not connected to the liquid circulation and recovery module 2. When drying is required, the seeds in the collection trays 21 are removed and placed into the drying system. In other embodiments, the liquid recycling module 2 can adopt a two-layer collection tank design, with a nylon mesh bag in the upper layer to collect seeds, and the liquid in the lower layer flowing out of the mesh bag and being pumped away into the storage tank for recycling.

[0050] Liquid filtration module: such as Figure 5 As shown, the separated liquid is filtered to ensure its recyclability. This module includes at least two filter cartridges, a first filter cartridge 31 and a second filter cartridge 32, each containing filter cotton and equipped with a three-way valve 22 at both ends. The three-way valve 22 at the inlet end of the filter cartridge is connected to the liquid circulation and recovery module 2, and the three-way valve 22 at the outlet end is connected to the inlet pump 4 via a recovery pipe 34, allowing the filtered liquid to be pumped back to the storage tank 5. The working principle of this filter 3 is as follows: First, the three-way valve 22 is set so that the liquid circulation and recovery module 2 is connected to the first filter cartridge 31 and the inlet pump 4 in sequence. At this time, the second filter cartridge 32 is not connected to the system, and the filter cotton and filter element of the second filter cartridge 32 can be disassembled and cleaned. Similarly, the liquid circulation and recovery module 2 can be connected to the second filter cartridge 32 and the inlet pump 4 in sequence. At this time, the first filter cartridge 31 is not connected to the system, and the filter cotton and filter element of the first filter cartridge 31 can be disassembled and cleaned.

[0051] Liquid storage module: Used to store filtered liquids, ensuring a stable supply and safe storage. The liquid dispensing module can also store prepared liquids for later use.

[0052] All modules of the equipment can be mounted on a frame with wheels for easy movement, or fixed to a support structure in the factory. It should be noted that during installation, a spacious, ventilated, and exhaust-equipped operating space and related facilities must be established for density sorting. The entire equipment has good airtightness to ensure that the sorted liquid will not leak.

[0053] To gain a more thorough and comprehensive understanding of the disclosure of this invention, its principles will be further explained below in conjunction with its usage.

[0054] For tobacco seeds, previous studies have found that seeds with a density between 1.00 g / ml and ρ < 1.15 g / ml have the highest germination potential and rate. Therefore, the procedure involves preparing a mixed liquid with a density of 1.00 g / ml using hexane and dichloromethane, with a liquid-to-seed volume ratio > 2:1. The mixture is then vibrated, allowed to stand, and the seeds are separated into layers. Seeds with a density < 1.00 g / ml suspended in the upper and middle portions of the liquid are separated, while the seeds at the bottom are retained. All the liquid is then poured off. A mixed liquid with a density of 1.15 g / ml is prepared using the same liquid and added to the seeds previously retained at the bottom, with a liquid-to-seed volume ratio > 2:1. The mixture is stirred, allowed to stand, and the seeds are separated again. Seeds with a density ≤ 1.15 g / ml suspended in the upper and middle portions are retained, while seeds with a density > 1.15 g / ml that have settled at the bottom are removed. This completes the sorting process. In this latter step, the amount of seeds with a density > 1.15 g / ml is generally very small, and it can be omitted depending on the actual situation.

[0055] The specific usage steps are as follows:

[0056] S1: The liquid metering module pumps the n-hexane and dichloromethane stored in the storage tank 5 into the mixing tank 72 of the mixing module 7 through the diaphragm metering pump 8. The impeller inside the mixing tank 72 stirs and mixes the liquid.

[0057] S2: The mixed liquid is pumped into the storage tank 5 by the inlet pump 4 for later use. It should be noted that a quantitative liquid dispensing device is installed below the storage tank 5 to deliver a quantitative amount of liquid to the density separation module 1.

[0058] S3: Seed tank 6 puts a quantitative amount of seeds into density separation module 1, and liquid storage tank 5 delivers a quantitative amount of liquid to density separation module 1;

[0059] S4: Vibrator 15 vibrates the liquid and seeds in density separation module 1, causing seeds of different densities to quickly separate into lower chamber 11 and upper chamber 13. After 3-5 minutes, straight-through valve 12 closes the channel between lower chamber 11 and upper chamber 13. Figure 7 As shown;

[0060] S5: The three-way valve 22 at the bottom of the lower chamber 11 is switched to the side of the high-density seed collection tray 21, discharging the liquid and high-density seeds in the lower chamber 11 into the high-density seed collection tray 21 of the liquid circulation and recovery module 2. The nozzle 14 sprays the wall of the lower chamber 11 to blow off the seeds attached to the inner wall of the chamber. Then, the three-way valve 22 is switched to the side of the low-density seed collection tray 21, and the straight valve 12 is opened, discharging the liquid and seeds in the upper chamber 13 into the low-density seed collection tray 21 of the liquid circulation and recovery module 2.

[0061] S6: After the liquid from the liquid circulation and recovery module 2 enters the filter 3, the filtered liquid is pumped to the storage tank 5 by the inlet pump 4. It should be noted that the inlet pump 4 has two inlet pipes, which are connected to the filter 3 and the mixing tank 72 respectively, and valves are installed on both inlet pipes. The inlet pump 4 can selectively pump the liquid from the liquid circulation and recovery module 2 or the liquid from the mixing tank 72.

[0062] S7: The drying device dries the seeds in the collection tray 21. The air inlet of the drying system is located above the collection tray 21 and blows downwards, while the air outlet is located on the side of the sealed container. The drying system dries the seeds on the collection tray 21. It should be noted that the drying system can be set up independently and is not connected to the liquid circulation and recovery module 2. When drying is required, the seeds in the collection tray 21 are removed and placed into the drying system.

[0063] The storage tank 5 has two pipes at its bottom, which are connected to the density separation module 1 and the recovery tank 9 respectively. Each pipe is equipped with a solenoid valve, which controls the flow of liquid in the storage tank 5.

[0064] It should be noted that this equipment and method can be used not only to separate tobacco seeds, but also to separate flower and medicinal seed seeds.

[0065] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the foregoing claims.

[0066] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A seed density specific classification apparatus, characterized by: The application relates to a liquid quantitative preparation module, a density separation module (1), a liquid circulation recovery module (2) and a liquid filtration module, wherein the liquid quantitative preparation module is used for preparing liquid with a preset density and delivering the liquid to the density separation module (1); the density separation module (1) is provided with a bin body for layering seeds with different densities; the density separation module (1) delivers the separated seeds to the liquid circulation recovery module (2); the liquid circulation recovery module (2) separates the seeds from the liquid; and the separated liquid is delivered to the liquid filtration module for filtration. The liquid quantitative preparation module comprises a mixing module (7), metering pumps (8), a n-hexane storage tank (91) and a dichloromethane storage tank (92); the n-hexane storage tank (91) and the dichloromethane storage tank (92) are used for respectively sealingly storing n-hexane and dichloromethane; the metering pumps (8) are provided with two and are used for respectively quantitatively pumping the n-hexane and the dichloromethane into the mixing module (7); the mixing module (7) comprises a mixing motor (71), a mixing tank (72) and a paddle; the mixing motor (71) drives the paddle to stir and mix the n-hexane and the dichloromethane in the mixing tank (72). The liquid quantitative preparation module and the density separation module (1) are provided with a liquid inlet pump (4) and a storage tank (5); the liquid inlet pump (4) pumps the liquid in the mixing tank (72) to the storage tank (5); the bottom of the storage tank (5) is provided with a valve and is connected with a pipeline of the density separation module (1) so as to quantitatively deliver the prepared liquid to the density separation module (1). The density separation module (1) comprises a lower bin (11), a valve and an upper bin (13); the valve is located between the lower bin (11) and the upper bin (13) and is used for separating seeds with different densities; the lower bin (11) is connected with the liquid circulation recovery module (2) through a pipeline. The lower bin (11) of the density separation module (1) is a double-cone container, the upper bin (13) is a cone container, an electric straight-through valve (12) is arranged between the lower bin (11) and the upper bin (13), and the lower bin (11) and the upper bin (13) further comprise a nozzle (14) and a vibrator (15); the nozzle (14) is connected with the storage tank (5) and is used for spraying seeds adhered to the inner wall of the bin body so that the seeds fall to the bottom of the container; and the vibrator (15) is used for vibrating the liquid and the seeds so as to quickly layer the seeds with different densities.

2. A seed density specific classification apparatus as claimed in claim 1, characterised in that: The application further comprises a liquid storage module, and the liquid filtration module stores the filtered liquid in the liquid storage module.

3. A seed density specific classification apparatus as claimed in claim 1, wherein: The liquid circulation and recovery module (2) comprises a sealed tank, two collecting trays (21) are arranged on both sides of the sealed tank, a conical liquid collecting hopper (24) is arranged below the collecting tray (21), the liquid collecting hopper (24) is communicated with the liquid filtration module, two feeding pipes (23) are arranged above the collecting tray (21), the feeding pipes (23) are connected with the density separation module (1) through three-way valves (22), the three-way valves (22) are used for distributing seeds with different densities to different collecting trays (21), and the collecting tray (21) is drawer-type sealingly arranged on both sides of the sealed tank.

4. A seed density specific classification apparatus as claimed in claim 3, wherein: The sealed tank is further connected with a drying system, an air inlet of the drying system is arranged above the collecting tray (21), an air outlet is arranged on the side of the sealed tank, and the drying system is used for drying the seeds on the collecting tray (21).

5. A seed density specific classification apparatus as claimed in claim 1, wherein: The liquid filtration module comprises a filter (3), the filter (3) is provided with at least a first filter cartridge (31) and a second filter cartridge (32), filter cotton is arranged in the first filter cartridge (31) and the second filter cartridge (32), and three-way valves (22) are arranged at both ends of the first filter cartridge (31) and the second filter cartridge (32), the three-way valve (22) at the liquid inlet end of the filter cartridge is connected with the liquid circulation and recovery module (2), and the three-way valve (22) at the liquid outlet end of the filter cartridge is connected with a liquid inlet pump (4).

6. A method of seed density sorting comprising the seed density sorting apparatus of any one of claims 1 to 5, characterized in that: The method comprises the following steps S1: The liquid quantitative preparation module quantitatively draws n-hexane and dichloromethane stored in a liquid storage tank (5) into a mixing tank (72) of a mixing module (7), and paddles in the mixing tank (72) are used for stirring and mixing the liquids; S2: The mixed liquid is drawn into the liquid storage tank (5) for standby use; S3: The seed tank (6) puts the quantitative seeds into the density separation module (1), and the liquid storage tank (5) delivers the quantitative liquid to the density separation module (1); S4: The vibrator (15) vibrates the liquid and the seeds in the density separation module (1), so that the seeds with different densities are quickly layered into the lower bin (11) and the upper bin (13), and the straight-through valve (12) closes the channel between the lower bin (11) and the upper bin (13); S5: The three-way valve (22) at the bottom of the lower bin (11) is switched to one side of the high-density seed collecting tray (21), the liquid and the seeds in the lower bin (11) are discharged into the high-density seed collecting tray (21) of the liquid circulation and recovery module (2), the nozzle (14) sprays the wall of the lower bin (11), and the seeds adhered to the inner wall of the bin are blown off; the three-way valve (22) is switched to one side of the low-density seed collecting tray (21), the straight-through valve (12) is opened, the liquid and the seeds in the upper bin (13) are discharged into the low-density seed collecting tray (21) of the liquid circulation and recovery module (2); S6: The liquid in the liquid circulation and recovery module (2) enters the filter (3) and then passes through the liquid inlet pump (4), and the liquid inlet pump (4) draws the filtered liquid into the liquid storage tank (5); S7: The drying device is used for drying the seeds in the collecting tray (21).

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